Asset composer

npm install dcompose
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CommonJS bundler for javascript and CSS.

What does it mean? It means you can write code which requires other code and... stylesheets:

var styles = require('./button.css');
var dependency = require('./button.js');



% npm install -g dcompose


There is a command line utility dcompose:

% dcompose --help
Usage: dcompose [options] entry

  -h, --help          Show this message and exit
  -v, --version       Print dcompose version
  -d, --debug         Emit source maps
  -w, --watch         Watch for changes and rebuild (--output should be passed)
  -o, --output        Set output directory
  --js                Bundle JS dependencies only
  --css               Bundle CSS dependencies only
  -t, --transform     Apply transform
  --css-transform     Apply CSS transform
  --global-transform  Apply global transform
  --extension         File extensions to treat as modules [default: .js]

Usage from Node.js is also possible:

var dcompose = require('dcompose');

dcompose('./entry.js', {debug: true})
  .bundleJS(function(err, bundle) {

Usage examples

Produce a bundle:

% dcompose ./app.js > ./app.bundle.js

You can bundle CSS dependencies separately:

% dcompose --css ./app.js > ./app.bundle.css

You can bundle JS dependencies separately:

% dcompose --js ./app.js > ./app.bundle.js

Produce a bundle with source map information (debug mode):

% dcompose --debug ./app.js > ./app.bundle.js

Produce a bundle and start watching on changes:

% dcompose --watch --output ./app.bundle.js ./app.js

Handling CSS dependencies

Regarding javascript dependencies this works exactly like browserify. Regarding stylesheet dependencies there are two strategies supported by dcompose:

By default CSS dependencies will be wrapped into CommonJS module which will append stylesheet to a DOM when executed first time. This is not superefficient but will provide a quick start for prototyping.

Another approach is to bundle CSS dependencies separately, for that there's --css option which will bundle only CSS dependencies from a dependency graph:

% dcompose --css ./app.js > ./app.bundle.css

After that you can include app.bundle.css like you normally would in <link> element.


dcompose(entries, opts)

Create a new composer object with the following arguments:

  • enrties is a single module specification or an array or those
  • opts is an options object
Module specification

You can specify a module name which will be resolved using Node modules resolving mechanism, so "jquery", "./React" or "./lib/router.js" would be fine.

Alternative you can specify an object of the following shape

  id: string,
  expose: boolean | string,
  entry: boolean,
  source: string | buffer,
  deps: {
    <local module id>: <absolute path to module source>,

All fields except id are optional:

  • expose — if true when module will be exposed using its id, if it's a string then it will be used as a public module identifier instead of its id

  • entry — if module should be executed when bundle is loaded (by default true for all modules in entries argument)

  • source — module source, if it's specified then module dependencies should be also specified

  • deps — an object which defined module dependencies in the format of mapping from local module ids (those use in require(...) calls to absolute filenames pointing to the deps' sources

  • transform — a single transform or an array of transforms, transform is a module id which exports transform function or transform function itself. Browserify and dgraph transform are supported.

  • cssTransform — a single CSS transform or an array of CSS transforms, transform is a module id which exports transform function or transform function itself. xcss transforms are supported.

  • extensions — an array of extensions to use then resolving a require with no extension provided, by default only .js files a re considered.

  • debug — emit source maps (works both from CSS and JS)

  • watch — start watching for source changes and emit update event


Composer object is an EventEmitter and emits the following events during lifecycle:

  • update — when an update to code in dependency graph occurs.


Produce bundle of JS and CSS dependencies.


Produce bundle of JS dependencies.


Produce bundle of CSS dependencies.

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